1. Field of the Invention
The present invention relates to an electronic watch having a built-in antenna.
2. Description of Related Art
As a type of an electronic watch, a radio wave watch with a built-in antenna is known. This type of watch has a watch case 1 made of a plastic, as shown in FIG. 6. The watch case 1 has two band connecting potions 2 which are provided at positions in the twelve o""clock side and the six o""clock side, although only that of the twelve o""clock side is shown in this figure. In the band connecting potion 2 in the twelve o""clock side, a containing concavity 3 is formed so as to open upwardly. In the containing concavity 3, an antenna 4 is contained. The antenna 4 is a bar antenna which comprises an iron core and a coil wounded around the core. Around the entirety of the periphery of the antenna 4, a cushion member 6 made of rubber sheet or the like is wounded. The upper portion of the containing concavity 3 is closed by a covering member 5 for covering the antenna 4. The covering member 5 comprises a plastic panel. The entirety of the periphery of the covering member 5 is welded to the watch case 1 around the upper portion of the containing concavity 3 by a welding method, e.g., a ultrasonic welding or the like.
At the central portion of the upper surface of the watch case 1, a watch glass 8 is provided to attach to the watch case by welding. On the periphery of the upper surface of the watch case 1, a bezel 7 is installed at a position between the covering member 5 and the watch glass 8. Inside the watch case 1, a watch module 9 is installed. The watch module 9 has at least one of the analog function and the digital function. The watch module 9 is electrically connected to the antenna 4 which is contained in the containing concavity 3. On the lower surface of the watch case 1, a case back 10 is attached through a waterproof ring 10a. 
However, the electronic watch with such a structure has the following problems.
That is, in such an electronic watch, the whole surface of the covering member 5 which covers the antenna 4 is exposed outside. When such an electronic watch is dropped by accident in the state that the side of the watch glass 8 takes a lower position, the electronic watch rotates so that the antenna 4 takes a lower position because of the large weight of the antenna. As a result, the outer surface of the covering member 5 comes into collision with a floor or the like, and the welding portion of the covering member 5 receives a direct impact from the floor or the like to be cracked or destroyed.
The electronic watch having such a structure has also following another problem.
That is, the electronic watch requires to wound a cushion member 6 around the antenna 4 in order to protect the antenna 4 from such an impact. When wounding the cushion member 6 around the antenna 4, the size of the antenna 4 comes to be larger, and as a result, the entirety of the watch must be large-sized.
An object of the invention is to provide an electronic watch having an antenna and a covering member for covering the antenna, in which the covering member is hard to be cracked or destroyed by an impact caused by dropping or the like.
In order to solve the above-described problem, in accordance with an aspect of the present invention, the electronic watch comprises: a watch case with a containing concavity which is formed in a peripheral portion thereof; an antenna contained in the containing concavity; a covering member fixed to the watch case, for covering the containing concavity containing the antenna; and a casing member provided with a supporting member which is attached to a periphery of the watch case to hold down the covering member, covering at least a portion of the covering member.
According to the invention, because at least a portion of the covering member which is fixed to the watch case, for covering the containing concavity containing the antenna is covered and held by a supporting member which is attached to a periphery of the watch case, it is possible to undertake a part of the impact caused by dropping or the like, by the supporting member. Accordingly, it is possible to protect the covering member from cracking or destruction caused by the impact of dropping or the like.
In this case, it is preferable to provide a cushion member between the covering member and the supporting member.
According to the electronic watch having such a structure, it is possible to weaken the impact caused by dropping or the like and accordingly to protect the covering member and antenna contained in the containing concavity from the impact caused by dropping and the like. Further, because it is unnecessary to wound a cushion member around the antenna which is required for the conventional technique, the size of the whole antenna is not required to be large. As a result, it is possible to miniaturize the whole electronic watch.